An atheist group has called on a school district in Ohio to put a stop to a pastor's voluntary lunchtime Bible study sessions with students.

In a letter to Indian Creek School District administrator Dr. T.C. Chappelear, the Wisconsin-based Freedom From Religion Foundation (FFRF) argued that it is unconstitutional for the district to allow the Bible studies during school hours at Indian Creek Middle School (ICMS).

The group also described the gospel presentations of Pastor Bobbyjon Bauman of the Valley Youth Network as "predatory conduct."

"It is unconstitutional for the district to offer religious leaders access to befriend and proselytize students during the school day on school property," the FFRF wrote, as reported by Christian News Network.

"This predatory conduct is inappropriate and should raise many red flags. The district cannot allow its schools to be used as recruiting grounds for churches during the school day," it continued.

The secularist group noted that it was alerted to the Bible study sessions by a local resident and it had also reviewed Bauman's social media posts, including one on Feb. 23 in which the pastor claimed that 165 students had attended that day.

Bauman wrote that he had shared the Gospel with the students using Romans 6:23 and noted that none of those who were in the four Bible study groups knew what the word "Gospel" meant.

The pastor said that the students were responsive to his message and 30 of them requested Bibles because they did not own one.

The letter from FFRF claims that Bauman had also explained in his post that ICMS Principal Holly Minch-Hick encouraged students to listen to him preach.

The FFRF contended that the school had "unconstitutionally entangled" itself with a religious message by allowing Church representatives to recruit students, adding that the practice alienates non-Christian students and school employees.

In the letter, the group said the Supreme Court had declared that programs of religious instruction on public school grounds violated the Establishment Clause of the Constitution.

The FFRF also cited the lawsuit that it filed when a public school allowed religious groups access to students during the school day. According to the FFRF, the Sixth Circuit Court of Appeals found the practice unconstitutional because it had no secular purpose, it communicated a message of government endorsement of religion and fostered excessive entanglement between state and religion.

The organization further argued Bauman's Bible studies were inappropriate even if they were voluntary in nature.

"Please note that it makes no difference that students are not required to attend these preaching sessions. Voluntariness does not excuse a constitutional violation," the FFRF stated.

"The district must immediately discontinue allowing Mr. Bauman, or any other preachers, access to students during the school day," it continued.